The present invention relates to a variable timing system, and in particular to a variable timing system for use in an engine of a vehicle.
One of the conventional variable timing systems is disclosed in the U.S. Pat. No. 5,067,450. This system includes a first member driven by an engine, a second member rotatably connected to a crank shaft, and means for adjusting an angular relative displacement therebetween. in addition, a damper is interposed between the first and second members in order to avoid an angular position change of the second member relative to the first member when a torque variation is applied to the second member. The damper has a plurality of meshing labyrinth grooves on the first and second members and viscous fluid between the labyrinth grooves. In order to prevent a leakage of the viscous fluid a sealing member is interposed between the first and second members.
However, in the foregoing structure, the sealing member also acts as a friction between the first member and the second member which should be displaced in the angular direction when the variable timing system is in operation.